Surface Engineering of Protein Nanoparticles Modulates Transport, Adsorption, and Uptake in Mucus

Protein nanoparticles have been demonstrated as effective
carriers
for protein antigens and therapeutics due to properties endowed by
their protein composition. They exhibit high protein to carrier yields,
biocompatibility, and heterogeneous surface properties. While protein
nanoparticles have been delivered via multiple routes, including intranasal,
their interactions with mucosal barriers have not been well studied
or modified. Biological barriers associated with intranasal delivery
consist of viscoelastic mucus that hinders material transport through
surface interactions and the underlying epithelium. Herein, we altered
protein nanoparticle surface properties and characterized interactions
with nasal mucus and the subsequent effects on diffusion, cellular
uptake, and immune cell maturation. Ovalbumin protein nanoparticles
were used, serving as a model vaccine nanoparticle. Unmodified ovalbumin
protein nanoparticles were compared to cationic ovalbumin particles
functionalized with amine groups, neutral particles functionalized
with polyethylene glycol, and zwitterionic particles coated layer-by-layer
(LBL) with chitosan and oligonucleotides. Transport analysis indicated
rapid diffusion of polyethylene glycol and LBL-modified ovalbumin
nanoparticles in porcine nasal mucus, while cationic particles were
mucoadhesive. Cellular uptake in the presence of mucus by epithelial
and dendritic cells was highest for particles containing positive
charges, both LBL and amine-functionalized. These particles also exhibited
the most diverse adsorbed protein corona from nasal fluids. The corona
impacted both dendritic cell uptake and maturation, with polyethylene
glycol and LBL modifications improving CD86 expression. Altogether,
surface modifications on protein-based nanocarriers are shown to facilitate
distinctive physical and cellular behavior associated with mucosal
delivery.